Vascular access device

ABSTRACT

An access device for placing a medical article within a body space includes a syringe, a needle, and a sheath which are employed together with a guide wire. The sheath can be coaxially and slideably disposed about the needle. During insertion of the sheath over the needle, guide wire and into the body space, the syringe provides a negative pressure to ensure that any air located between the inside diameter of the sheath and the outside diameter of the needle is drawn into the needle rather than into the body space. In certain embodiments, a dilator is coaxially and slideably disposed about the needle and within the sheath.

CROSS REFERENCE TO PRIORITY APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Pat. App. 62/155,368 entitled “VASCULAR ACCESS DEVICE” filedon Apr. 30, 2015 and to U.S. Provisional Pat. App. 62/209,841 entitled“VASCULAR ACCESS DEVICE” filed on Aug. 25, 2015, the disclosures ofwhich are hereby incorporated by reference in their entireties.

BACKGROUND Field

The present disclosure is generally directed to access devices forintroducing and/or delivering a medical article (such as, for example, acatheter, cannula, sheath, etc.) into a body space, such as, forexample, an artery, vein, vessel, body cavity, or drainage site, andmore specifically, to a distal tip section of such devices.

Description of the Related Art

Various medical devices, for example, catheters, cannulas, sheaths,etc., are often introduced into a patient, for example, in an artery,vein, body cavity, or drainage site, to deliver fluids to or withdrawfluids from the patient. For example, a catheter or vascular sheath canbe introduced into a patient's blood vessel using a Raulerson technique.This technique involves inserting an introducer needle attached to aRaulerson syringe into the patient's blood vessel and then inserting aguide wire through the rear of the syringe plunger and into the vessel.The Raulerson syringe and needle are removed leaving the guide wireextending into the patient. A skin-nick may be performed adjacent to theguide wire to enlarge the puncture site. A catheter or other medicalarticle can be threaded over the guide wire and into the patient. Oncethe catheter is in a desired location, the guide wire is removed.

The above technique requires exchanges over the guide wire, whichpresents the risk of losing cannulation, lost guide wire, andcontamination. Further, during the skin-nick step the guide wire may besevered due to the guide wire being exposed. The overall technique istime intensive risking movement of the medical article(s) and guide wirerelative to the patient.

SUMMARY

The access devices described herein advantageously provide improvedmechanisms for confirming vascular access and achieving medical deviceplacement within the vasculature.

In some embodiments, an access device for placing a medical articlewithin a body space includes a syringe, a needle, and a sheath coaxiallydisposed about the needle. In certain embodiments, the access devicefurther includes a dilator disposed coaxially about the needle andwithin the sheath. The syringe includes a hollow barrel having a plungerslideably disposed therein. The syringe functions as a standard airtight syringe as well as a device which provides a passageway for aguide wire into a patient's vasculature.

The plunger comprises a central channel and valve element disposed inthe central channel. A normally closed centrally disposed slit oraperture is formed in the center of the valve element.

The hollow barrel supports a needle affixed to the tip thereof. Theneedle includes an exterior portion extending outwardly from the tip ofthe hollow barrel. The needle further includes an interior portionhaving an aperture formed therethrough adjacent to the tip of the hollowbarrel. The interior portion extends into the interior of the hollowbarrel such that at least a portion of the interior portion is at leastpartially disposed within the centrally disposed channel in the plungerduring use.

Disposed concentrically around the exterior portion of the needle is asheath. The sheath releaseably secures to the syringe to allow thesheath to be slid in a distal direction over the exterior portion of theneedle and into the patient. Once the syringe is removed leaving thesheath, a catheter may be inserted through the sheath and into thepatient. The sheath may be pealable so as to allow the sheath to beremoved from around an inserted catheter and from the patient.

In certain embodiments, a dilator is disposed concentrically around theexterior portion of the needle and within the sheath. A distal end ofthe dilator extends beyond a distal end of the sheath. The dilator canreleaseably secure to one or both of the syringe and the sheath. Beingreleasably secured to the syringe allows the dilator to be slid inconcert with the sheath in a distal direction over the exterior portionof the needle and into the patient. Once the distal ends of the dilatorand sheath are disposed within the patient and the syringe is removed,the dilator is disengaged from the sheath and then removed. Once thesyringe and dilator are removed leaving the sheath, a catheter may beinserted through the sheath and into the patient. The sheath may bepealable so as to allow the sheath to be removed from around an insertedcatheter and from the patient.

In use the vascular access device is aspirated by the retraction of theplunger permitting fluid to pass into the interior of the syringe barrelthrough the aperture formed on the interior needle portion. During thisaspiration, air is prevented from entering the valve chamber by thevalve element.

Then a guide wire may be passed through the central channel of theplunger and the interior and exterior portions of the needle to reachthe blood vessel. The guide wire passes through the valve element toform a seal therewith to prevent either liquid or air from passingthrough the valve element during the introduction of the guide wire intothe patient.

The sheath is then slid over the exterior portion of the needle andguide wire and into the vasculature of the patient. The syringe and theguide wire are removed from the patient leaving the sheath. In certainembodiments, the sheath comprises a valve element for preventing liquidfrom flowing through the sheath.

In embodiments which include a dilator, the dilator is initiallyreleasably secured to the syringe with the sheath being releasablysecured to the dilator. Releasably securing the dilator to the sheathensures the distal end of the dilator extends beyond the distal end ofthe sheath during their insertion into the vasculature. The dilator isthen disengaged from the syringe while still being engaged with thesheath. Together, the dilator and sheath are then slid over the exteriorportion of the needle and guide wire and into the vasculature of thepatient. The syringe and guide wire are then removed from the patientleaving the dilator and the sheath. The dilator is disengaged from thesheath and slid in a proximal direction out of the sheath. In certainembodiments, the syringe, guide wire, and dilator and removed from thesheath at the same time. In certain embodiments, the sheath comprises avalve element for preventing liquid from flowing through the sheath.

In some embodiments, the sheath includes a sheath body, a hub, and avalve. The valve may include an annular member and a sealing member. Thesheath body includes a generally flexible tubular structure, a proximalend, and a distal end and defines a longitudinal axis. The hub iscoupled with the proximal end of the sheath body, and the sheath bodyand hub have aligned openings forming a passage therethrough. Theannular member of the valve is disposed against a surface of the hubfacing the sheath body and includes an opening therethrough. The sealingmember of the valve has an engagement portion coupled with a structureof the sheath assembly disposed generally between the surface of the huband the distal end of the sheath body. The sealing member also has aseal portion projecting into sealing engagement with the opening in theannular member in a sealing position and disposed away from the openingin the annular member in an open position.

In some embodiments, the access device for placing a medical articlewithin a body space includes a barrel and a plunger slidingly disposedin the barrel. The plunger has a channel sized and shaped to receive aguide wire therethrough. The barrel defines a fluid chamber. The accessdevice further includes an interior needle portion at least partiallydisposed in the channel. The interior needle portion includes anaperture through a side wall of the interior needle portion and into thefluid chamber. The access device further includes an exterior needleportion extending from the barrel and in flow communication with theinterior needle portion and the fluid chamber. The access device furtherincludes a sheath coaxially disposed about the exterior needle portionand slideable along the exterior needle portion. A distal end of thesheath is positioned proximal to a distal end of the exterior needleportion.

In some embodiments, the access device for placing a medical articlewithin a body space includes a syringe and a needle extending from thesyringe. The syringe has a channel configured to receive a guide wireextending through the needle. The access device further includes asheath coaxially disposed about the needle and slideable along theneedle.

In some embodiments, a method for placing a medical article within abody space includes the steps of penetrating a blood vessel with anaccess device. The access device includes a syringe, a needle extendingfrom the syringe, and a sheath coaxially disposed about the syringe. Thesyringe has a channel in flow communication with the needle. The methodfurther includes feeding a guide wire through the channel, the needle,and into the blood vessel and sliding the sheath along the needle in adistal direction until at least a portion of the sheath is disposed inthe blood vessel. The method further includes removing the syringe, theneedle, and the guide wire from the blood vessel leaving the sheath.

In some embodiments, a dilator is employed between the exterior portionof the needle and the interior surface of the sheath to increase a sizeof the opening into the vasculature of the patient for the sheath.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features, aspects, and advantages of theembodiments of the invention are described in detail below withreference to the drawings of various embodiments, which are intended toillustrate and not to limit the embodiments of the invention. Thedrawings comprise the following figures in which:

FIG. 1 is a perspective view of an embodiment of an access device havinga syringe with a needle coaxially aligned with a medical article such asa sheath. A guide wire for use with the access device is also shown.

FIG. 2 is a plan view of the embodiment depicted in FIG. 1 without theguide wire.

FIG. 3 is a proximal end view of the sheath from FIG. 1.

FIG. 4 is a plan view of the sheath of FIG. 3.

FIGS. 5 and 6 are a side isometric view and an exploded side isometricview, respectively, of another embodiment of the sheath from FIG. 1 thatincludes a valve element.

FIG. 7 is a side cross-sectional view of the sheath of FIG. 5 taken at7-7.

FIGS. 8 and 9 are enlarged views of a section of the sheath of FIG. 7showing a valve element in a closed and opened position, respectively.

FIGS. 10, 11, and 12 are enlarged views of a section of an embodiment ofa sheath that includes an annular member, a resilient plate, and sealingelement.

FIG. 13 is a cross-section view of the syringe from FIG. 1 incombination with the valved sheath from FIG. 5 and shows a plunger ofthe syringe in an advanced state.

FIG. 14 is similar to FIG. 13 except the plunger of the syringe is in aretracted state.

FIG. 15 is an enlarged cross-section view from FIG. 13 taken at 15-15.

FIG. 16 is a cross-section view of the access device illustrated in FIG.13 penetrating a body.

FIG. 17A is a cross-section view similar to FIG. 16 except the needlehas penetrated the vasculature and the plunger has been partiallyretracted creating a negative pressure in the syringe body.

FIG. 17B is an enlarged partial cross-section view from FIG. 17A of adistal end of the needle.

FIG. 18A is a cross-section view similar to FIG. 17 except a guide wirehas been fed through the plunger and needle and into the vasculature ofthe patient.

FIG. 18B is a cross-section view similar to FIG. 18A except the guidewire has been extended further into the vasculature of the patient.

FIG. 19 is a cross-section view similar to FIG. 18B except the sheathhas been slid along the exterior portion of the needle and into thepatient's vasculature.

FIG. 20 is a cross-section view similar to FIG. 19 except the syringeand guide wire have been removed from the patient and the sheath.

FIG. 21 is a cross-section view similar to FIG. 20 except a catheter isaligned with the sheath for insertion into the patient's vasculature.

FIG. 22 is a cross-section view similar to FIG. 21 except the catheterhas been inserted through the sheath and into the patient's vasculature.

FIG. 23 is a cross-section view similar to FIG. 22 except two portionsof the sheath are being peeled away from each other to remove the sheathfrom encircling the catheter.

FIG. 24 is a plan view of a dilator that can be used with the accessdevice of FIG. 1.

FIG. 25 is a cross-sectional view taken along the lines 25-25 in FIG.24.

FIG. 26 is a perspective view of an embodiment of an access devicehaving a syringe with a needle coaxially aligned with medical articlessuch as a sheath and a dilator. A guide wire for use with the accessdevice is also shown.

FIG. 27 is a plan view of the embodiment depicted in FIG. 26 without theguide wire.

FIG. 28 is a cross-section view of the syringe from FIG. 26 and shows aplunger of the syringe in an advanced state.

FIG. 29 is similar to FIG. 28 except the plunger of the syringe is in aretracted state.

FIG. 30 is an enlarged cross-section view from FIG. 28 taken at 30-30.

FIG. 31 is an enlarged view of a portion of the embodiment depicted inFIG. 30 and illustrates portions of the needle, dilator, and sheath.

FIG. 32 is an enlarged cross-sectional view of the embodiment depictedin FIG. 31 taken at a longitudinal location wherein the needle, dilator,and sheath overlap along line 32-32.

FIG. 33A is a cross-section view of the access device illustrated inFIG. 28 penetrating a body.

FIG. 33B is an enlarged partial cross-section view from FIG. 33A of adistal end of the needle.

FIG. 34A is a cross-section view similar to FIG. 33A except the needlehas penetrated the vasculature and the plunger has been partiallyretracted creating a negative pressure in the syringe body.

FIG. 34B is an enlarged partial cross-section view from FIG. 34A of adistal end of the needle.

FIG. 35A is a cross-section view similar to FIG. 34A except a guide wirehas been fed through the plunger and needle and into the vasculature ofthe patient.

FIG. 35B is a cross-section view similar to FIG. 35A except the guidewire has been extended further into the vasculature of the patient.

FIG. 36 is a cross-section view similar to FIG. 35B except the dilatorand sheath have been slid along the exterior portion of the needle andinto the patient's vasculature.

FIG. 37 is a cross-section view similar to FIG. 36 except the syringeand the guide wire have been removed from the patient leaving thedilator and the sheath in the vasculature.

FIG. 38 is a cross-section view similar to FIG. 37 except the dilatorhas been removed from the patient and the sheath.

FIG. 39 is a cross-section view similar to FIG. 38 except a catheter isaligned with the sheath for insertion into the patient's vasculature.

FIG. 40 is a cross-section view similar to FIG. 39 except the catheterhas been inserted through the sheath and into the patient's vasculature.

FIG. 41 is a cross-section view similar to FIG. 40 except two portionsof the sheath are being peeled away from each other to remove the sheathfrom encircling the catheter.

DETAILED DESCRIPTION

In various circumstances a physician may wish to introduce a catheter orsheath into a space within a patient's body, for example, a blood vesselor drainage site, to introduce fluids to the space or remove fluids fromthe space. Various access devices are known in the art. Examples of animproved access device are described in U.S. patent application Ser. No.14/238,832, entitled “ACCESS DEVICE WITH VALVE,” filed Feb. 13, 2014,published as US 2014/0207069 on Jul. 24, 2014, the entire contents ofwhich is incorporated by reference herein. FIGS. 1 and 2 illustrate anembodiment of an access device 20 that can be used, for example, inperforming a modified Raulerson technique to introduce a catheter orsheath into a patient's blood vessel. Certain embodiments of the accessdevice 20 may further include a dilator 124 as is illustrated in FIGS.24 and 25. An embodiment of the access device that includes the dilator124 is illustrated in FIGS. 26 through 41.

While the access devices 20 described herein in the context of vascularaccess, the access device also can be used to access and place a medicalarticle (e.g., catheter or sheath) into other locations within apatient's body (e.g., a drainage site) and for other purposes (e.g., fordraining an abscess).

The present embodiment of the access device is disclosed in the contextof placing an exemplary single-piece, tubular medical article into abody space within a patient. Once placed, the tubular article can thenbe used to receive other medical articles (e.g., catheters, guide wires,etc.) to provide access into the body space and/or be used to provide apassage way for introducing fluids into the body space or removing(e.g., draining) fluids from the body space. In the illustratedembodiment, the tubular medical article is a sheath or catheter that isconfigured primarily to provide a fluid passage into a vein. Theprinciples of the present invention, however, are not limited to theplacement of single piece sheaths or catheters, or to the subsequentinsertion of a medical article via the sheath or catheter. Instead, itwill be understood in light of the present disclosure that the accessdevice disclosed herein also can be successfully utilized in connectionwith placing one or more other types of medical articles, includingother types of sheaths, fluid drainage and delivery tubes, and single ormulti-lumen catheters directly in the patient or indirectly via anothermedical article.

For example, but without limitation, the access devices disclosed hereincan also be configured to directly or indirectly place central venouscatheters, peripherally inserted central catheters, hemodialysiscatheters, surgical drainage tubes, tear-away sheaths, multi-piecesheaths, PICC lines, IV lines, scopes, as well as electrical conduit forwires or cables connected to external or implanted electronic devices orsensors. As explained above, the medical articles listed above may beplaced within the patient via a medical article that was placed withinthe patient via the access device.

Further, the embodiments disclosed herein are not limited to co-axialinsertion of a single medical article. For example, two catheters may beinserted in the patient via an inserted sheath or a second catheter maybe inserted in the patient via an inserted first catheter. Further, inaddition to providing a conduit into the vessel or other body space, themedical article inserted via the access device can form a lumen that isin addition to the lumen(s) of the subsequently inserted medicalarticle. One skilled in the art can also find additional applicationsfor the devices and systems disclosed herein. Thus, the illustration anddescription of the access device in connection with a sheath (e.g., formicro puncture applications) is merely exemplary of one possibleapplication of the access device.

FIG. 1 is a perspective view of an embodiment of an access device 20having a syringe 24 with a needle 22 coaxially aligned with a medicalarticle such as a sheath 26. A guide wire 28 for use with the accessdevice is also shown. FIG. 2 is a plan view of the embodiment depictedin FIG. 1. With reference to FIGS. 1 and 2, an example embodiment of theaccess device 20 includes the needle 22, the syringe 24, and the tubularsheath 26. In the illustrated embodiment, the access device 20 alsoincludes the guide wire 28. The sheath 26 can be coaxially disposedabout the needle 22. The access device 20 allows the introduction of theguide wire 28 and subsequently the sheath 26 into a patient's body.

The syringe 24 comprises a syringe barrel 30 and a substantiallycylindrical plunger 32 slideably disposed therein. As described morefully hereinafter, the access device 20 is capable of functioning as astandard air tight syringe as well as a device to introduce a catheteror guide wire 28 into the patient's body.

The barrel 30 comprises a hollow substantially cylindrical body having ahollow barrel tip 38 to support the needle 22 and a finger graspingelement 40 formed on opposite ends thereof. The needle 22 comprises afirst or exterior needle portion 42 including a piercing point 44extending outwardly generally from the hollow barrel tip 38. The needle22 further includes a second or interior needle portion 46 extendinginwardly from the barrel tip 38 into the interior of the hollowsubstantially cylindrical syringe barrel 30. An aperture 48 is formedthrough the second portion 46 near a bottom of a fluid chamber 34. Theaperture 48 extends, or provides a path, through the wall or side of thesecond needle portion 46. The aperture 48 can allow for a fluid, such asblood, to flow into the fluid chamber 34 during use of the access device20. Blood flow into the fluid chamber 34 indicates to the physician orhealthcare provider that the piercing point 44 of the exterior needleportion 42 has punctured a blood vessel. The aperture 48 can have avariety of shapes and orientations on the second needle portion 46. Forexample, the aperture 48 illustrated in FIG. 15 has a round shape.However, the shape of the aperture 48 is not limited to the illustratedembodiment and may be oblong, square, or another shape.

The hollow barrel tip 38 comprises a first barrel tip section or needlehub 50 and a second barrel tip section 52 operatively receiving andsupporting the first and second portions 42 and 46, respectively. Anintermediate channel 54 is cooperatively formed between the first andsecond barrel tip sections 50 and 52 in coaxial alignment with the firstor exterior needle portion 42 and second or interior needle portion 46.When the plunger 32 is fully advanced within the syringe barrel 30, themajor portion of the second or interior portion 46 is disposed within acentrally disposed channel 56 in the plunger 32.

The sheath 26 includes a generally flexible tubular structure, aproximal end or hub 60, and a distal end or body 58, and defines a lumenalong a longitudinal axis. The sheath hub 60 is coupled with theproximal end of the sheath body 58 and has a passage therethrough.Certain embodiments of the sheath 26 further include a valve coupledwith a distal face of the hub 60. For example, the valve could be in theform of a diaphragm. The diaphragm provides fluid communication betweenthe lumen and the passage when open and has a proximal face configuredto seal when closed. The diaphragm can be configured to seal against adevice disposed in the passage, diaphragm and lumen of the sheath 26and/or when there is no device disposed in the sheath 26. Certainembodiments of the sheath 26 are splittable as described in more detailbelow. Accordingly, embodiments of the sheath 26 component of the accessdevice 20 may be splittable and or include a valve structure for sealingthe lumen through the sheath 26.

FIG. 3 is a proximal end view of the sheath 26 from FIG. 1. FIG. 4 is aplan view of the sheath 26 of FIG. 3. As shown in FIGS. 3 and 4, thesheath 26 includes a sheath body 58 and a sheath hub 60. In theembodiment illustrated in FIGS. 3 and 4, the sheath body 58 and/orsheath hub 60 can be optionally splittable along one or more split lines68. A splittable sheath 26 provides the advantage of allowing a portionof or the entire sheath body 58 to be removed depending on the type ofcatheter or medical article that is to be inserted into the vessel afteremploying the access device 20. For example, after the catheter or othermedical article is inserted into the vessel, a portion of the sheathbody 58 can be separated or peeled-away and removed to reduce clutter atthe access site. A peel-away sheath 26 can include perforations,serrations, skives, or other structures, or include other materials(e.g., PTFE with bismuth) to allow the physician or healthcare providerto remove easily a portion or the entire sheath body 58. In certainembodiments, the sheath 26 is not splittable.

The sheath hub 60 can include a locking structure 70 configured toengage, for example, a second locking structure 64 of the exteriorneedle portion 42. In certain embodiments which include a dilator, thelocking structure 70 of the sheath hub 60 may secure to the dilator. Thesheath body 58 may be a single piece sheath through which a catheter orother medical article is inserted into the vessel. In such anembodiment, the sheath body 58 forms a conduit for insertion of thecatheter or other medical article. In addition to providing a conduit,the sheath 26 or a portion of the sheath 26 can form a lumen that is inaddition to the lumen(s) of the catheter. For example, an equivalent toa triple lumen catheter can be formed by inserting a dual lumen catheterthrough the sheath body 58 with the sheath body 58 itself forming athird lumen. The sheath body 58 can be manufactured from a clear or atleast somewhat transparent material to allow the physician or healthcareprovider to see blood flowing through the sheath body 58.

In some such embodiments, the sheath hub 60 may comprise radiallyextending wings, handle structures, or tabs 66 to allow for easy releaseand removal of the sheath body 58 from other parts of the access device20. Tabs 66 can have any of a number of different shapes and/or surfacefeatures to facilitate them being gripped, and are not limited to thesubstantially T-shape shown. Tabs 66 are separable, to allow thesplittable sheath 26 to separate along one or more split lines, such asa predetermined split or separation line 68. The split line 68 canextend through either or both the sheath hub 60 and the sheath body 58.The split line(s) 68 can extend generally parallel to one or morelongitudinal axes defined by the sheath body 58 and/or sheath hub 60,but in some embodiments, the split line(s) 68 can extend substantiallynon-parallel. As illustrated most clearly in FIG. 23, splitting thesheath 26 along the split line 68 can separate the sheath 26 into two ormore symmetrical or asymmetrical portions (e.g., halves).

In some embodiments, the sheath 26 has a separable lip forming thelocking structure 70, allowing engagement of the sheath 26 with otherelements described above, such as the needle 22, while allowingseparation along split line 68. Additional embodiments of a splittablesheath body and/or hub that can be employed with the sheath 26 are shownand described, for example, in FIGS. 23A-23B, and the correspondingsupporting text (e.g., paragraphs [0225]-[0229]), of U.S. patentapplication Ser. No. 13/319,998, entitled “ACCESS DEVICE WITH VALVE,”filed Nov. 10, 2011, published as US 2012/0065590 on Mar. 15, 2012, theentire contents of which is incorporated by reference herein. In someapplications, the wings 66 are sized to provide the healthcare providerwith leverage for breaking apart the sheath hub 60. The sheath hub 60and/or the sheath body 58 may comprise two or more portions (e.g.halves) connected by a thin (e.g., frangible) membrane. The membrane canbe sized to hold the two or more portions of the sheath hub 60 and/orsheath body 58 together until the healthcare provider decides to removethe sheath hub 60 and/or sheath body 58 from the access device 20. Thehealthcare provider manipulates the wings 66 to break the membrane andsever one or more portions of the sheath hub 60 into separate orpartially separated pieces.

FIGS. 5-9 illustrate another embodiment of a sheath 26A that can be usedwith the needles, guide wires, and other elements described herein in asimilar manner to the previously described sheath 26. The sheath 26Aillustrated in FIGS. 5-9 includes a valve element 78. FIGS. 5 and 6 area side isometric view and an exploded side isometric view, respectively,of the sheath 26A from FIG. 1. FIG. 7 is a side cross-sectional view ofthe sheath 26A of FIG. 5 taken at 7-7. FIGS. 8 and 9 are enlarged viewsof a section of the sheath 26A of FIG. 7 showing the valve element 78 ina closed and opened position, respectively.

Sheath 26A can include a sheath body 58A and a sheath hub 60A, with aninner cavity 72 extending through or along a portion of sheath body 58Aand/or sheath hub 60A (e.g., along one or more longitudinal axesthereof). The sheath hub 60A can extend from a proximal end of thesheath body 58A. The sheath body 58A and/or sheath hub 60A can beoptionally splittable along one or more split lines 68A. In someembodiments, the sheath body 58A and/or sheath hub 60A can be splittablealong two or more split lines 68A, to form two or more separablesections or halves, such as sheath hub sections 74 and 76. Theembodiments of the sheath 26A, including body 58A and hub 60A, can begenerally similar to the embodiments of sheaths, sheath bodies, and/orsheath hubs discussed elsewhere herein.

With reference to FIGS. 6-9, the sheath 26A can include a valve element78 configured to substantially seal a portion of inner cavity 72. Thevalve element 78 can include a resilient plate 80 supporting a sealingelement 82. The resilient plate 80 can be supported by a portion of thesheath body 58A and/or hub 60A such that a portion (e.g., a sealingportion 84) of the resilient plate 80 can extend (e.g., radiallyinwardly) into and substantially seal the inner cavity 72. The valveelement 78 can be positioned between a proximal portion 86 of the innercavity 72 and a distal portion 88 of the inner cavity 72, such that theproximal portion 86 and the distal portion 88 can be substantiallysealed with respect to each other. The portions 86, 88 can comprise anyof a variety of sizes and shapes, and are shown with an approximatelycircular cross-sectional shape for illustrative purposes only. In thedepicted embodiment, the proximal portion 86 of the inner cavity 72comprises at least a region having a cross-sectional area that is lessthan the distal portion 88, to facilitate sealing of the valve 78against the portion 86, while allowing the valve 78 to flex and movedistally into the distal portion 88, as described further herein. Inthis arrangement, the valve 78 can be configured to substantiallyinhibit flow through the inner cavity 72 in a proximal direction, whilenot substantially inhibiting the passage of articles such as a dilatoror needle through the cavity.

The valve element 78 can be adapted to flex or move between a closed, orsubstantially sealed position (for example, as shown in FIGS. 7 and 8),and an open, or substantially unsealed position (for example, as shownin FIG. 9), through flexation or flexing of the resilient plate 80. Thevalve element 78 can move between an open and closed position throughpassage of a fluid (or gas), a device, or through an operation by a user(for example, using an external lever or other device attached to theresilient plate 80). In the closed position, a sealing surface 90 on aproximal surface of the sealing element 82 can contact or otherwiseengage with a corresponding sealing surface 92 on a distal surface of atleast one of the splittable sheath body and hub 58A, 60A. Theinteraction of the sealing surfaces 90 and 92 can inhibit passagethrough the cavity 72 in the proximal direction. Notably, pressureagainst the valve element 78 in a proximal direction can press thesealing surfaces 90 and 92 further together. In some embodiments, thismechanism can be sufficiently resilient to withstand pressuresassociated with human blood vessels to prevent a loss of blood throughthe valve. In some embodiments, the sealing element 82 includes a raisedportion, such as substantially dome-shaped portion 94. The dome-shapedportion 94 can prevent or reduce the likelihood of contact between thesealing surface 90 and a device 96, when the device 96 is extendedthrough cavity 72. For example, if the sheath 26A is stored with adevice extended through the cavity 72, for example, the needle 22 asdescribed herein, if the device 96 sets or sticks to another portion ofthe sheath 26A, it will do so to the raised portion 94, and not to aportion of the sealing surface 90. As such, the raised portion 94 canprevent damage to the sealing surface 90 of the sealing element 82 byextended forceful contact with the device 96, and thus extend thesealing capability and life of the valve element 78.

In some embodiments, the resilient plate 80 is configured such that thesealing surface 90 of the sealing element 82 is biased or preloadedagainst the sealing surface 92 of the splittable sheath body and/or hubsuch that the valve 78 is preloaded in the closed position. This biasingcan enhance the above-described inhibition of passage of matter in theproximal direction. Additionally, the biasing can help the valve element78 inhibit passage of matter such as the flow of fluid or gas (e.g.,blood or air) or passage of a device in a distal direction (e.g.,longitudinally) within the cavity 72. For example, the bias towards theclosed position can be strong enough to resist a force (or crackingpressure) in the distal direction to open the valve element 78. In someembodiments, the preload or bias of the valve element 78 can besufficient to prevent gas from being drawn distally through the cavity72, and into a patient due to, for example, negative pressure created bya human during a normal pulse. Notably, drawing gas into a blood vesselcan cause serious health effects such as an embolism.

The resilient plate 80 can comprise any of a variety of materials withsufficient rigidity to support the sealing element 82 and substantiallyseal the inner cavity 72, and with sufficient flexibility to allow thevalve element 78 to flex or move between the open and closed positionsdescribed herein. The resilient plate 80 can comprise a bio-compatiblemetal or plastic, or various composites or combinations thereof.Preferably, the resilient plate 80 can comprise a material with reducedsusceptibility to cold-setting, such that a needle, dilator, catheter,or other medical article can be extended through the cavity 72, with thevalve element 78 in an open position, as described above, and packagedtogether for a period of time within the sheath 26A, withoutcompromising the valve features (e.g., its flexibility and ability toseal the cavity 72 when in a closed position). In some embodiments, theresilient plate 80 can comprise, Nickel, Titanium, and/or steel (e.g.,stainless steel, spring steel, etc.), or various alloys or combinationsthereof. In some embodiments, the resilient plate 80 comprises NiTi(Nitinol), or NiTi SE. In some embodiments, the resilient plate 80 cancomprise a shape-memory alloy to facilitate its movement between anopened and closed position and to prevent cold-setting for extendedperiods of time such as 2 years.

The sealing element 82 can comprise any of a variety of materials thatcan substantially seal the inner cavity 72 when in contact with orbiased against the sealing surface 92. In some embodiments, the sealingelement 82 can comprise metal, plastic, rubber, or other suitablebiocompatible materials such as polyisoprene, silicone, polyurethane, orother elastic polymers. In some embodiments, the Shore A hardness of thesealing element 82 can be within a range of approximately 5 to 90, or insome embodiments, 10 to 70, or in some embodiments, approximately 15 to50, or in some embodiments, approximately 30. In some embodiments, thesealing element 82 can be coated or include other surface treatments,such as a siliconized surface to facilitate low-friction sliding ofvarious elements along its surface (such as device 96). Even further, insome embodiments the resilient plate 80 and the sealing element 82 canbe formed of the same material, such that the valve element 78 canoptionally be a single unitary piece.

The resilient plate 80 and/or element 82 can be formed in a number ofdifferent ways, such as molding (e.g., injection), stamping and thelike, and can be formed separately or integrally. The resilient plate 80and sealing element 82 can be attached to each other in a variety ofways, such as with adhesive, bonding (e.g., ultrasonic, thermal, etc.),fasteners, overmolding, and the like. A primer or non-stick coating orsurface treatment can be applied to the plate 80 and/or sealing element82 to facilitate their attachment to each other during the manufacturingthereof. In some embodiments, a plurality of plates 80 and/or elements82 can be formed in a single molding or stamping step, with severabletabs to allow the plates 80 and/or elements 82 to be used individually.With respect to the bending properties of the resilient plate 80,described above, in some embodiments the resilient plate 80 can bepretreated to have certain mechanical characteristics prior to itscombination with the sealing element 82.

The valve element 78, as depicted by way of the resilient plate 80, canattach to the sheath 26A by a variety of means. In some embodiments itcan be glued or bonded to the sheath 26A. In other embodiments, theresilient plate 80 can attach to the sheath 26A by molding orovermolding. In further embodiments, the resilient plate 80 can bemolded integrally with the sheath 26A (or a portion thereof such as thesheath hub halt). When formed integrally, it may be desirable to givethe hub 60A or body 58A a substantially greater thickness than theresilient plate 80, such that the hub or body maintains a higherrigidity. In other embodiments the resilient plate 80 can attach to thesheath 26A by a mechanical compression, such as where the sheath hub 60Aor body 58A includes a groove that receives the plate, and allows it tobe press-fit into position.

The resilient plate 80 can be attached to various portions of the sheathhub 60A and/or body 58A. In some embodiments, the sheath hub 60A and/orbody 58A can comprise two or more separate pieces that are positionedand attached with respect to each other such that a portion of theresilient plate 80 is clamped between a portion of the sheath hub 60Aand/or body 58A. As best shown in FIGS. 6, 8, and 9, the sheath hub 60Acan comprise a proximal portion 98 and a distal portion 100. Theproximal portion 98 and the distal portion 100 are configured to engagewith each other such that the valve element 78, by way of a mountingportion 102 of the resilient plate 80, can be supported or clampedtherebetween within a groove or gap 104 (as shown in FIG. 9). Portions98, 100 can comprise any of the materials described herein generally forthe sheath 26A and other components thereof, such as the sheath hub 60Aand the sheath body 58A. In one embodiment, the portion 98 comprises ABSplastic. In one embodiment, the portion 100 comprises a K resin. Theportions 98, 100 can engage with each other using any of a variety ofattachment means and methods known or described herein, such as bonding,adhesive (e.g., solvents), and the like.

The valve element 78, and resilient plate 80, can be attached to one ormore sections of the sheath hub 60A and/or body 58A that separate alongline(s) 68A. Preferably, the resilient plate 80 is attached to only oneseparable section of the sheath 26A, such as sheath hub section 74, tofacilitate the separation of the valve 78 from the sheath hub section 76during the splitting of sheath 26A. Additionally, the plate 80 can beattached to only one separable section of the sheath 26A to facilitatethe flexing and movement of the resilient plate 80 and the sealingelement 82 within the inner cavity 72. In other embodiments, where thevalve element 78 is attached to multiple separable portions of thesheath hub 60A and/or body 58A, the valve element 78 can also beseparable by similar structures.

FIGS. 10, 1 1, and 12 are enlarged views of a section of an embodimentof the sheath 26A that includes an annular member 106, a resilient plate80A, and sealing element 82A. The plate 80A and sealing element 82A canbe similar to the resilient plate 80 and sealing element 82 shown inFIGS. 6-9 and described herein. The annular member 106 can function likean O-ring in some respects. As shown, the annular member 106 includes acentral bore 108 configured to receive the domed-shaped portion 94A ofthe sealing element 82A when the valve is in a closed position. A topsurface of the annular member 106 tapers so that the annular member isthinner proximate the bore 108 than at a location outward of the bore108, e.g., at the outer edge. The taper can be downwardly from an uppersurface in some embodiments. A bottom surface of the annular member 106can be substantially straight or flat. The annular member 106 is placedagainst the sealing surface 92 so that in a closed position, the sealingelement 82A seals against the annular member 106 rather than the sealingsurface 92. The annular member 106 can be made of a relatively softmaterial, and can be thin enough to tear during splitting of the sheath26A. The annular member 106 can advantageously compensate for possiblemolding imperfections and/or misalignment in the manufacture andassembly of the sheath hub, for example, due to being constructed from arelatively soft and compliant material. The annular member 106 alsoadvantageously reduces the size of the aperture to be sealed by thesealing element 82A compared to the sealing surface 92, which canproduce a greater vacuum hold to bias the sealing element 82A in aclosed position with the same spring pre-loading force of the resilientplate 80A. Additionally, the annular member 106 can act as a seal arounda device introduced into the patient through the sheath 26A to maintaina seal when the valve 78 is in an open position to accommodate thedevice. The annular member 106 can therefore act as a seal independentof the sealing element 82A. In some embodiments, the annular member 106can stretch to accommodate and/or conform to various devices that can beintroduced through the sheath 26A.

In some embodiments, the sealing element 82A can be made of a relativelyhard material, for example, polyurethane or polycarbonate. Inclusion ofa relatively soft annular member 106 can advantageously allow thesealing element 82A to be made of a relatively hard material because themore compliant annular member 106 can compensate for moldingimperfections, misalignment, and the like for which a relatively hardsealing element 82A may not be able to compensate as effectively. Therelatively hard material can advantageously reduce possible damage tothe resilient plate 80A. Additionally, with a sealing element 82A madeof a relatively softer material, for example, silicone, the resilientplate 80A may bend to some extent anywhere along its length when thevalve is opened. With a sealing element 82A made of a relatively hardermaterial, bending of the resilient plate 80A may be relatively morelimited to a pivot axis 110, which can reduce possible damage and/orwear to the resilient plate 80A. The relatively hard material can alsobetter resist tearing and/or other wear. Such tearing or wear canadversely affect the effectiveness of the seal or expose sharp portionsof the resilient plate 80A, which can cut or otherwise damage otherinstruments, for example a dilator as described herein, inserted intoand/or removed from the sheath 26A through the valve 78.

FIG. 13 is a cross-section view of the syringe 24 from FIG. 1 incombination with the sheath 26A from FIG. 5 and shows a plunger 32 ofthe syringe 24 in an advanced state. The sheath 26A illustrated in FIG.13 includes a valve element 78. FIG. 14 is similar to FIG. 13 except theplunger 32 of the syringe 24 is in a retracted state. FIG. 15 is anenlarged cross-section view from FIG. 13 taken at 15-15. With referenceto FIGS. 13-15, the second needle hub 52 is disposed on a distal end ofthe interior needle portion 46. The second needle hub 52 can include alocking structure 112 at a proximal part of the second needle hub 52 toallow the physician or healthcare provider to lock the second needle hub52 to the barrel tip 38. Of course the access device 20 could beprovided to the physician with the second needle hub 52 already lockedto the barrel tip 38.

Similarly, the first needle hub 50 is disposed on a proximal end of theexterior needle portion 42. The first needle hub 50 can include alocking structure 114 at a proximal part of the first needle hub 50 toallow the physician or healthcare provider to lock the first needle hub50 to the second needle hub 52. The first needle hub 50 can also includea locking structure 64 at a distal portion of the first needle hub 50 toallow the physician or healthcare provide to secure (e.g., releaseablysecure) another medical article such as sheath hub 60 to the firstneedle hub 50. The locking structures 112, 114 can be, for example, Luerlock or Luer slip connection.

Although in some embodiments the first needle hub 50, the second needlehub 52, and/or the sheath hub 60 can connect via one or more luerconnections that may prevent the passage of gases, additional mechanismsknown in the art or described herein can also attach one or more of thestructures. For example, in the depicted embodiment the first needle hub50 can include locking structure 64 that can releaseably hook to thelocking structure 70 on a ledge portion or lip of the sheath hub 60. Insome embodiments, a taper within the sheath 26, 26A (also used for aluer connection with a needle) can facilitate a seal between the sheath26, 26A and the first needle hub 50.

The syringe barrel 30 includes the fluid chamber 34 with the plunger 32movable between advanced and retracted states slideably disposed withinthe fluid chamber 34. The central channel 56 includes the aperture 48disposed in the fluid chamber 34. The central channel 56 is formedlongitudinally through the hollow syringe barrel 30 and plunger 32. Thevalve 116 is disposed in operative relationship relative to the centralchannel 56 to prevent passage of fluid through the central channel 56during flushing or aspirating of the access device 20 or during theintroduction or withdrawal of a guide wire 28 through the centralchannel 56. Fluid is permitted to flow from the patient's body into thefluid chamber 34 through the aperture 48. The central channel 56 isconfigured to maintain the guide wire 28 in a substantially straightconfiguration while the guide wire 28 is disposed within the centralchannel 56.

The exterior needle portion 42 has a sufficiently long length to accessa targeted subcutaneous body space and has a sufficient gauge size towithstand the insertion forces when accessing the body space withoutcausing undue trauma. For many applications, the needle body can have alength between 3-20 cm, and more preferably between 3-10 cm. Forexample, to access a body space (e.g., a vessel) in the thorax of anadult human, the exterior needle portion 42 preferably has a length of 7cm or greater, and more preferably has a length of 9 cm or greater, andmost preferably has a length of 9 to 10 cm. The size of the needlepreferably is 18 gauge or smaller, and more preferably between 18-28gauge, and most preferably between 18-26 gauge for micro-punctureapplications (e.g., peripheral IVs). For applications with a neonate,the length and gauge of the exterior needle portion 42 should besignificantly shorter and smaller, for example preferably between 3-4 cmand between 26-28 gauge. In some embodiments, the exterior needle body42 includes an echogenic portion that can be used in combination withultrasound to help position the needle in the desired location.

The plunger 32 comprises a valve 116 and a central channel 56 formedtherethrough. The inner end of the plunger 32 is received within thebarrel 30, while the opposite end includes the finger grasping element40. The valve 116 can comprise one or more one-way valve elements. Forexample, the valve elements may comprise a flexible resilient hollowhemispheric member. A normally closed centrally disposed slit oraperture is formed in the center of the valve element.

In use the access device 20 is aspirated by the retraction of theplunger 32 as shown in FIG. 14 permitting fluid to pass into theinterior of the barrel 30 through the aperture 48. During aspiration airis prevented from entering the central channel 56 by the valve 116. Onceaspirated, the access device 20 may then be flushed. While flushing, thevalve 116 prevents liquid from passing through the central channel 56into the valve 116. Thus, the access device 20 functions as an ordinarysyringe.

As shown in FIG. 14 when the plunger 32 is retracted, the interiorneedle portion 46 of the needle 22 remains disposed within the centralchannel 56. In this configuration the guide wire 28 may be passedthrough the access device 20 and into the blood vessel or body cavity.The guide wire 28 passes through the centrally disposed slot formed inthe valve 116 which forms a seal therewith to prevent either liquid orair from passing through the valve 116 during the introduction of theguide wire 28.

FIG. 16 is a cross-section view of the access device 20 illustrated inFIG. 13 penetrating a body 118. FIG. 17A is a cross-section view similarto FIG. 16 except the needle 22 has penetrated the vasculature and theplunger 32 has been partially retracted creating a negative pressure inthe syringe barrel 30. At this stage of use, a channel is formed betweenthe needle 22 and the syringe 24, to allow, for example, blood to flowinto the fluid chamber 34. The aperture 48 in the interior needleportion 46 allows blood to flow through the sidewall of the needle 22and into the fluid chamber 34. FIG. 17B is an enlarged partialcross-section view from FIG. 17A of a distal end of the needle 22. Inuse, the piercing point 44 enters the blood vessel 122. When entering anartery, the arterial blood pressure causes the plunger 32 to retract asthe blood enters the fluid chamber 34 through the aperture 48. Whencannulating the blood vessel 122, the access device 20 is aspirated bythe retraction of the plunger 32 to create a vacuum or negative pressurewithin the fluid chamber 34 permitting fluid to pass into the barrel 30through the aperture 48. In certain embodiments, the physician orhealthcare provider can insert a transduction probe in the rear of thesyringe 24 and through the valve 116 as known in the art. The physicianor healthcare provider can observe a wave form associated with the probeto determine if venous access has been achieved.

FIG. 18A is a cross-section view similar to FIG. 17 except a guide wire28 has been fed through the plunger 32, the valve 116, and needle 22 andinto the blood vessel 122 of the patient. Once the physician orhealthcare provider has located the needle 22 within the target bloodvessel 122, the physical or healthcare provider feeds the guide wire 28through the plunger 32 while maintain the position of the plunger 32relative to the barrel 30. Preferably the needle 22 is also held stillwhile the guide wire 28 is fed through the syringe 24 and into thepatient. During the insertion procedure, the valve 116 seals against theguide wire 28 preventing air from entering the central channel 56 tomaintain the negative pressure in the fluid chamber 34. A guide wireadvancer as known in the art may be employed when feeding the guide wire28 through the syringe 24. For example, if the guide wire 28 has acurved or J tip, an advancer may be employed to straighten the tipfacilitating feeding of the guide wire 28 into the central channel 56 ofthe plunger 32. FIG. 18B is a cross-section view similar to FIG. 18Aexcept the guide wire 28 has been extended further into the vasculatureof the patient.

FIG. 19 is a cross-section view similar to FIG. 18B except the sheath26A has been slid along the exterior portion 42 of the needle 22 andinto the patient's vasculature. During insertion of the sheath 26A overthe needle 22, guide wire 28 and into the blood vessel 122, the existingnegative pressure in the syringe 24 ensures that any air located betweenthe inside diameter of the sheath 26A and the outside diameter of theneedle 22 is drawn into the needle 22 rather than into the blood vessel122. If necessary, a skin-nick can be performed to enlarge the puncturesite adjacent to the needle 22.

FIG. 20 is a cross-section view similar to FIG. 19 except the syringe 24and guide wire 28 have been removed from the patient leaving the sheath26A properly inserted within the blood vessel 122. During the removalprocess, the internal volume of the stationary sheath 26A increases asthe needle 22 and guide wire 28 are removed which creates negativepressure in the sheath 26A ensuring air is not drawn into the bloodvessel 122 during removal.

The described procedure is less time intensive than the Raulersonsyringe techniques and does not require multiple exchanges over theguide wire when employed with multiple medical articles (e.g., dilatorover guide wire, sheath over guide wire, catheter over guide wire). Ifsuch exchanges were performed over the guide wire, such actions presentthe risk of losing cannulation, lost guide wire, and contamination.Further, during the skin-nick step the needle 22 protects the guide wire28 from being accidentally severed. The described technique reduces therisk of movement of the sheath 26, 26A and guide wire 28 relative to thepatient during the procedure. The above described procedure is lessbloody, especially if a valved sheath 26A is employed, and reduces theexposure of the physician or healthcare provider to blood.

FIG. 21 is a cross-section view similar to FIG. 20 except a catheter 120is aligned with the sheath 26A for insertion into the patient'svasculature. FIG. 22 is a cross-section view similar to FIG. 21 exceptthe catheter 120 has been inserted through the sheath 26A and into thepatient's vasculature, specifically the targeted blood vessel 122.

FIG. 23 is a cross-section view similar to FIG. 22 except two portionsof the sheath 26A are being peeled away from each other to remove thesheath 26A from encircling the catheter 120. The sheath 26A issplittable along one or more split lines 68, 68A (see FIGS. 4 and 5). Asplittable sheath 26A provides the advantage of allowing a portion of orthe entire sheath body 58 to be removed depending on the type ofcatheter or medical article that is to be inserted into the vessel afteremploying the access device 20. For example, after the catheter 120 isinserted into the blood vessel 122, a portion of the sheath body 58 isseparated or peeled-away and removed to reduce clutter at the accesssite. The peel-away sheath 26A can be first slid in a proximal directionalong the catheter 120 until the sheath 26A is removed from the patientand then split apart. Alternatively, the sheath 26A can be initiallysplit prior to the entire sheath 26A being removed from the patient.After the remainder of the sheath 26A is removed from the patient, thephysician or healthcare provided can continue splitting the sheath 26A.Of course, the sheath 26A could be split in concert with its removalfrom the patient as is illustrated in FIG. 23. In certain embodiments,the sheath 26A is not splittable.

FIG. 24 is a plan view of a dilator 124 that can be used with the accessdevice 20 of FIG. 1 to facilitate insertion of a larger sheath 26, 26Ainto the vasculature. In such an embodiment, the dilator 124 is disposedbetween the needle 22 and the sheath 26, 26A. FIG. 25 is across-sectional view taken along the lines 25-25 in FIG. 24.

FIG. 26 is a perspective view of an embodiment of an access device 200similar to the access device 20 except the access device 200 includesthe dilator 124 illustrated in FIGS. 24 and 25. The dilator 124 isdisposed between the needle 22 and the sheath 26, 26A. Thus, the accessdevice 200 has a syringe 24 with a needle 22 coaxially aligned with thesheath 26 and the dilator 124. The guide wire 28 for use with the accessdevice 200 is also shown. FIG. 27 is a plan view of the embodimentdepicted in FIG. 26. With reference to FIGS. 26 and 27, an exampleembodiment of the access device 200 includes the needle 22, the syringe24, the dilator 124, and the tubular sheath 26. In the illustratedembodiment, the access device 200 also includes the guide wire 28. Thedilator 124 can be coaxially disposed about the needle 22. The sheath 26can be coaxially disposed about the dilator 124. The dilator 124 expandsan opening or passage created by the needle 22. The expanded passagefacilitates subsequent introduction of the sheath 26. The access device200 allows the introduction of the guide wire 28, and subsequently thedilator 124 and finally the sheath 26 into a patient's body. The syringe24 and sheath 26 are the same as the syringe 24 and sheath 26 describedwith respect to FIG. 1. In certain embodiments, the syringe 24 andsheath 29 include coupling structures to releasably couple to thedilator 124.

With reference to FIGS. 24 through 27, the dilator 124 is illustrated.The dilator 124 includes a generally flexible tubular structure, aproximal end or hub 128, and a distal end or body 134, and defines alumen along a longitudinal axis. The dilator hub 128 is coupled with theproximal end of the dilator body 134 and has a passage therethrough.

The dilator hub 128 can include a first locking structure 130 to engagethe locking structure 64 of the exterior needle portion 42 and a secondlocking structure 132 to engage with the sheath hub 60. In certainembodiments, the dilator hub 128 does not include locking structures.For example, a distal surface of the dilator hub 128 may abut against aproximal surface of the sheath hub 60 while a proximal surface of thedilator hub 128 abuts against a distal surface of the needle portion 42of the syringe 24.

A distal portion 134 of the dilator body 126 can include a taperingouter surface which extends beyond a distal end of the sheath body 58.In this way, the distal portion 134 enters the skin and vasculatureprior to the sheath body 58 entering the skin and vasculature. Thetapering outer surface of the distal portion 134 gradually expands thepuncture site to a larger size than created by the needle 22 toaccommodate the distal end of the sheath body 58. Of course the dilator124 is not required for use of the access device.

FIG. 28 is a cross-section view of the syringe 24 from FIG. 26 and showsa plunger 32 of the syringe 24 in an advanced state. FIG. 29 is similarto FIG. 28 except the plunger 32 of the syringe 24 is in a retractedstate. FIG. 31 is an enlarged cross-section view from FIG. 28 taken at31-31. With reference to FIGS. 28-30, the first locking structure 130 ofthe dilator hub 128 is engaged with the locking structure 64 of theexterior needle portion 42 to allow the physician or healthcare providerto (e.g., releaseably secure) lock the dilator 12.4 relative to thebarrel tip 38. The second locking structure 132 of the dilator hub 128is engaged with the sheath hub 60 to allow the physician or healthcareprovider to secure (e.g., releaseably secure) the dilator 124 relativeto the sheath 26, 26A. Of course the access device 200 could be providedto the physician with the dilator 124 already locked to the exteriorneedle portion 42 and the sheath hub 60. The locking structures 130, 132can be, for example, Luer lock or Luer slip connection.

Although in some embodiments the first needle hub 50, the second needlehub 52, the dilator hub 128 and/or the sheath hub 60 can connect via oneor more luer connections that may prevent the passage of gases,additional mechanisms known in the art or described herein can alsoattach one or more of the structures. For example, in the depictedembodiment the first needle hub 50 can include locking structure 136that can releaseably hook to a ledge portion or lip of the dilator hub128. In some embodiments, a taper within the dilator 124 can facilitatea seal between the dilator 124 and the first needle hub 50.

FIG. 32 is an enlarged cross-sectional view of the embodiment depictedin FIG. 31 taken at a longitudinal location wherein the needle 32,dilator 124, and sheath 26 overlap along line 32-32. FIG. 33A is across-section view of the access device 200 illustrated in FIG. 28penetrating a body 118. The dilator 124 and the sheath 26A have yet topenetrate the body. FIG. 33B is an enlarged partial cross-section viewfrom FIG. 33A of a distal end of the needle 22.

In FIG. 34A, the needle 22 has penetrated the vasculature and theplunger 32 has been partially retracted creating a negative pressure inthe syringe barrel 30. The dilator 124 and the sheath 26A have yet topenetrate the vasculature. At this stage of use, a channel is formedbetween the needle 22 and the syringe 24, to allow, for example, bloodto flow into the fluid chamber 34. The aperture 48 in the interiorneedle portion 46 allows blood to flow through the sidewall of theneedle 22 and into the fluid chamber 34. FIG. 34B is an enlarged partialcross-section view from FIG. 34A of a distal end of the needle 22. Inuse, the piercing point 44 enters the blood vessel 122. When entering anartery, the arterial blood pressure causes the plunger 32 to retract asthe blood enters the fluid chamber 34 through the aperture 48. Whencannulating the blood vessel 122, the access device 20 is aspirated bythe retraction of the plunger 32 to create a vacuum or negative pressurewithin the fluid chamber 34 permitting fluid to pass into the barrel 30through the aperture 48. In certain embodiments, the physician orhealthcare provider can insert a transduction probe in the rear of thesyringe 24 and through the valve 116 as known in the art. The physicianor healthcare provider can observe a wave form associated with the probeto determine if venous access has been achieved.

FIG. 35A is a cross-section view similar to FIG. 34A except a guide wire28 has been fed through the plunger 32, the valve 116, and needle 22 andinto the blood vessel 122 of the patient. The dilator 124 and the sheath26A have yet to penetrate the vasculature. Once the physician orhealthcare provider has located the needle 22 within the target bloodvessel 122, the physical or healthcare provider feeds the guide wire 28through the plunger 32 while maintain the position of the plunger 32relative to the barrel 30. Preferably the needle 22 is also held stillwhile the guide wire 28 is fed through the syringe 24 and into thepatient. During the insertion procedure, the valve 116 seals against theguide wire 28 preventing air from entering the central channel 56 tomaintain the negative pressure in the fluid chamber 34. A guide wireadvancer as known in the art may be employed when feeding the guide wire28 through the syringe 24. For example, if the guide wire 28 has acurved or J tip, an advancer may be employed to straighten the tipfacilitating feeding of the guide wire 28 into the central channel 56 ofthe plunger 32. FIG. 35B is a cross-section view similar to FIG. 34Aexcept the guide wire 28 has been extended further into the vasculatureof the patient. The dilator 124 and the sheath 26A have yet to penetratethe vasculature.

FIG. 36 is a cross-section view similar to FIG. 35B except the sheath26A and the dilator 124 have been slid along the exterior portion 42 ofthe needle 22 and into the patient's vasculature. During insertion ofthe sheath 26A and dilator 124 over the needle 22 and guide wire 28 andinto the blood vessel 122, the existing negative pressure in the syringe24 ensures that any air located between an inside diameter of the sheath26A and an outside diameter of the needle 22 and/or between an outsidediameter of the dilator 124 and an inside diameter of the sheath 36A isdrawn into the needle 22 rather than into the blood vessel 122. Inaddition to employing the dilator 124 in certain embodiments, askin-nick can be performed to enlarge the puncture site adjacent to theneedle 22 facilitating insertion of the dilator 124 into the patient.

FIG. 37 is a cross-section view similar to FIG. 36 except the syringe 24and the guide wire 28 have been removed from the patient leaving thedilator 124 and the sheath 26A in the vasculature. During the removalprocess, the internal volume of the stationary sheath 26A increases asthe needle 22 and the guide wire 28 are removed which creates negativepressure in the sheath 26A ensuring air is not drawn into the bloodvessel 122 during removal.

FIG. 38 is a cross-section view similar to FIG. 37 except the dilator124 has been removed from the patient and the sheath 26A. The sheath 26Ais left properly inserted within the blood vessel 122. The dilator 124may be removed after the syringe 24 and the guide wire 28 are removed orin concert with removal of the syringe 24 and the guide wire 28. Duringthe removal process, the internal volume of the stationary sheath 26Aincreases as the dilator 124 is removed which creates negative pressurein the sheath 26A ensuring air is not drawn into the blood vessel 122during removal.

The described procedure is less time intensive than the Raulersonsyringe techniques and does not require multiple exchanges over theguide wire when employed with multiple medical articles (e.g., dilatorover guide wire, sheath over guide wire, catheter over guide wire). Ifsuch exchanges were performed over the guide wire, such actions presentthe risk of losing cannulation, lost guide wire, and contamination.Further, during the skin-nick step the needle 22 protects the guide wire28 from being accidentally severed. The described technique reduces therisk of movement of the sheath 26, 26A and guide wire 28 relative to thepatient during the procedure. The above described procedure is lessbloody, especially if a valved sheath 26A is employed, and reduces theexposure of the physician or healthcare provider to blood.

FIG. 39 is a cross-section view similar to FIG. 38 except a catheter 120is aligned with the sheath 26A for insertion into the patient'svasculature. FIG. 40 is a cross-section view similar to FIG. 39 exceptthe catheter 120 has been inserted through the sheath 26A and into thepatient's vasculature, specifically the targeted blood vessel 122.

FIG. 41 is a cross-section view similar to FIG. 40 except two portionsof the sheath 26A are being peeled away from each other to remove thesheath 26A from encircling the catheter 120. The sheath 26A issplittable along one or more split lines 68, 68A (see FIGS. 4 and 5). Asplittable sheath 26A provides the advantage of allowing a portion of orthe entire sheath body 58 to be removed depending on the type ofcatheter or medical article that is to be inserted into the vessel afteremploying the access device 200. For example, after the catheter 120 isinserted into the blood vessel 122, a portion of the sheath body 58 isseparated or peeled-away and removed to reduce clutter at the accesssite. The peel-away sheath 26A can be first slid in a proximal directionalong the catheter 120 until the sheath 26A is removed from the patientand then split apart. Alternatively, the sheath 26A can be initiallysplit prior to the entire sheath 26A being removed from the patient.After the remainder of the sheath 26A is removed from the patient, thephysician or healthcare provided can continue splitting the sheath 26A.Of course, the sheath 26A could be split in concert with its removalfrom the patient as is illustrated in FIG. 41. In certain embodiments,the sheath 26A is not splittable.

Although this disclosure has been described in the context of certainembodiments and examples, it will be understood by those skilled in theart that the disclosure extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses and obviousmodifications and equivalents thereof. In addition, while severalvariations of the embodiments of the disclosure have been shown anddescribed in detail, other modifications, which are within the scope ofthis disclosure, will be readily apparent to those of skill in the art.It is also contemplated that various combinations or sub-combinations ofthe specific features and aspects of the embodiments may be made andstill fall within the scope of the disclosure. It should be understoodthat various features and aspects of the disclosed embodiments can becombined with, or substituted for, one another in order to form varyingmodes of the embodiments of the disclosure. Thus, it is intended thatthe scope of the disclosure herein should not be limited by theparticular embodiments described above.

What is claimed is:
 1. An access device for placing a medical articlewithin a body space, the access device comprising: a barrel and aplunger slidingly disposed in the barrel, the plunger having a channelsized and shaped to receive a guide wire therethrough, the barreldefining a fluid chamber; an interior needle portion at least partiallydisposed in the channel, the interior needle portion comprising anaperture extending through a side wall of the interior needle portionand into the fluid chamber; a needle hub disposed on an exterior needleportion extending from the barrel and being in flow communication withthe interior needle portion and the fluid chamber, the needle hubcomprising a first locking structure at a proximal part of the needlehub and a second locking structure at a distal part of the needle hub; asheath coaxially disposed about the exterior needle portion andslideable along the exterior needle portion, a distal end of the sheathbeing positioned proximal to a distal end of the exterior needleportion; and a dilator disposed about the exterior needle portion andwithin the sheath, the dilator comprising a dilator hub and a dilatorbody, a distal end of the dilator body positioned distal to the distalend of the sheath, wherein the first locking structure is configured toreleasably secure the needle hub to the barrel, and wherein the secondlocking structure is configured to releasably secure the needle hub tothe dilator hub.
 2. The access device of claim 1, wherein the sheath issplittable into a plurality of portions.
 3. The access device of claim2, wherein the sheath comprises a sheath body and a sheath hub, thesheath body being a tubular structure of sufficient flexibility toextend without kinking through the skin of a patient and into and alongthe patient's vessel, and wherein the sheath body includes apre-determined line along which the sheath body is splittable into theplurality of portions.
 4. The access device of claim 3, wherein thepre-determined line is parallel to a longitudinal axis of the sheathbody.
 5. The access device of claim 1, wherein the sheath comprises avalve.
 6. The access device of claim 5, wherein the sheath comprises asheath body and a sheath hub, the sheath hub defining an inner cavity,and wherein the valve is disposed in the inner cavity.
 7. The accessdevice of claim 5, wherein the valve is configured to seal against theexterior needle portion.
 8. The access device of claim 1, wherein theplunger comprises a valve, the valve being configured to seal againstthe guide wire disposed in the channel.
 9. An access device for placinga medical article within a body space, the access device comprising: asyringe and a needle extending from the syringe, the syringe having achannel configured to receive a guide wire extending through the needle,the needle comprising a first locking structure and a second lockingstructure, wherein the syringe comprises a barrel and a plungerslidingly disposed in the barrel, wherein the plunger comprises a valveand a valve channel in flow communication with the valve, the valvebeing configured to seal against the guide wire disposed in the valvechannel; a sheath coaxially disposed about the needle and slideablealong the needle; and a dilator disposed about the needle and within thesheath, a distal end of the dilator positioned distal to a distal end ofthe sheath, wherein the first locking structure is configured toreleasably secure the needle to the syringe, and wherein the secondlocking structure is configured to releasably secure the needle to thedilator.
 10. The access device of claim 9, wherein the sheath ispeelable.
 11. The access device of claim 9, wherein the sheath comprisesa sheath valve.
 12. The access device of claim 11, wherein the sheathvalve is configured to seal against the needle.
 13. A method for placinga medical article within a body space, the method comprising:penetrating a blood vessel with an access device, the access devicecomprising: a syringe and a needle extending from the syringe, thesyringe having a channel configured to receive a guide wire extendingthrough the needle, the needle comprising a first locking structure anda second locking structure, a sheath coaxially disposed about theneedle, and a dilator disposed about the needle and within the sheath, adistal end of the dilator positioned distal to a distal end of thesheath, wherein the first locking structure is configured to releasablysecure the needle to the syringe, and wherein the second lockingstructure is configured to releasably secure the needle to the dilator;feeding the guide wire through the channel, the needle, and into theblood vessel; sliding the sheath along the needle in a distal directionuntil at least a portion of the sheath is disposed in the blood vessel;and removing the syringe, the needle, and the guide wire from the bloodvessel leaving the sheath.
 14. The method of claim 13, wherein thesyringe comprises a barrel and a plunger slidingly disposed in thebarrel, and wherein penetrating the blood vessel further comprisesretracting the plunger in the barrel to create a negative pressure inthe syringe.
 15. The method of claim 13, further comprising inserting amedical article into the blood vessel through the sheath.
 16. The methodof claim 15, further comprising peeling the sheath into a plurality ofportions for removal from the medical article.
 17. The method of claim13, further comprising: sliding the dilator along the needle in a distaldirection until at least a portion of the dilator is inserted intotissue; and removing the syringe, the needle, the dilator, and the guidewire from the body of the patient while leaving the sheath in the bloodvessel.
 18. The method of claim 13, wherein removing the syringe, theneedle, and the guide wire from the blood vessel is performedsimultaneously.